Open gap film roll core

Abstract

The disclosure generally relates to a film roll core used for winding a polymeric film around, an apparatus for winding the polymeric film on the film roll core, a process of winding the polymeric film on the film roll core, and a rolled film on the film roll core. The disclosure more particularly relates to an open gap film roll core that is capable of reducing defects in wound films.

What is claimed is: 
     
       1. A film roll core, comprising:
 a cylindrical tube having an outer surface; 
 a compliant layer disposed on the outer surface and having an initial thickness, t c ; and 
 a longitudinal gap in the compliant layer, the longitudinal gap defined by a first edge of the compliant layer and a second edge of the compliant layer, the first edge and a the second edge separated by a gap width, W, sized to accommodate a starting end of the film, the gap width between about 1/16 inches (1.588 mm) and about ⅜ inches (9.25 mm), 
 wherein the first edge of the compliant layer is compressed to a first thickness, t c1 , when a web of film is wound around the film roll core, wherein the second edge of the compliant layer is compressed to a second thickness, t c2 , when the web of film is wound around the film roll core, wherein the first thickness, t c1 , is less than second thickness, t c2 , and wherein the first thickness, t c1 , is less than the initial thickness, t c . 
 
     
     
       2. The film roll core of  claim 1 , wherein the compliant layer is adhered to the outer surface. 
     
     
       3. The film roll core of  claim 1 , further comprising an adhesive disposed on at least a portion of an exterior surface of the compliant layer. 
     
     
       4. The film roll core of  claim 1 , wherein the longitudinal gap is parallel to a rotation axis of the cylindrical tube. 
     
     
       5. The film roll core of  claim 1 , wherein the longitudinal gap comprises a spiral. 
     
     
       6. The film roll core of  claim 1 , wherein the compliant layer comprises an open-cell foam or a closed-cell foam. 
     
     
       7. The film roll core of  claim 1 , wherein the compliant layer comprises a polyurethane, a polyethylene, a silicone, or a rubber. 
     
     
       8. The film roll core of  claim 1 , wherein the longitudinal gap includes a cross-section that comprises a rectangular shape, a tapered shape, a vee-shape, an inverted vee-shape, or a combination thereof. 
     
     
       9. A roll of film, comprising:
 a film core comprising:
 a cylindrical tube having an outer surface; 
 a compliant layer disposed on the cylindrical tube outer surface and having an initial thickness, t c ; 
 
 a longitudinal gap in the compliant layer defined by a first edge of the compliant layer and a second edge of the compliant layer, the longitudinal gap having a gap width between about 1/16 inches (1.588 mm) and about ⅜ inches (9.25 mm); and 
 a web of film wound around the film core, 
 wherein a first film edge of the web of film is disposed within the longitudinal gap, 
 wherein the first edge of the compliant layer has a first thickness, t c1 , due to compressive forces imparted by the web of film wound around the film core, wherein the second edge of the compliant layer has a second thickness, t c2 , due to the compressive forces imparted by the web of film wound around the film core, wherein the first thickness, t c1 , is less than second thickness, t c2 , and wherein the first thickness, t c1 , is less than initial thickness, t c .